REVIEW: The Jungle Book, Chichester Festival Theatre, until February 3.

It’s difficult to imagine why anyone would think it a good idea to come up with a new musical version of The Jungle Book.

And yet, despite the precedent, despite all the obvious weight of expectation, writer Jessica Swale and composer Joe Stilgoe pull it off admirably with a show which is fresh, vibrant, witty, fun – and perhaps most important of all – original.

There’s still a slight feeling that we aren’t in the presence of the finished product, but there is an awful lot right on the night, most notably in a genuinely-lovely performance from Keziah Joseph as Mowgli.

This is a Jungle Book pitched very much as a show about identity, and Joseph, reluctant to give up her assumed wolf-cub identity, tugs at the heart-strings with a beautiful song about finding out just who exactly she is. Doubly interesting to have a female Mowgli.

Joseph brings the story to life compellingly as the little boy adopted by the oddest of couples – Deborah Oyelade as Bagheera and Dyfrig Morris as Balloo – until the day he’s forced the accept that the jungle really isn’t his natural home.

And yet, of course, somehow it is – as the show’s ingenious framing device and clever closing moments show us.

Alongside her, Morris is brilliant as Baloo, even if he does look like a little like a lion who’s mistakenly stumbled out of The Wizard of Oz. Joseph’s Mowgli is open and engaging – and sure to charm the kiddies. But it is Morris who ramps up the laughs, a terrific performance pitched at exactly the right level, not least in his post-interval tummy rumblings.

Elsewhere, the production needs to address the fact that when the whole company is singing it’s impossible to make out the words. And while the production is so obviously so different in conception to the Disney version and manages everywhere else to avoid all associations, Baloo’s opening song seems perilously close to King of the Swingers.

Much more oomph needs to be given to Shere Khan’s opening number; in fact, despite the children in the audience, the whole character of Shere Khan could do with considerably more menace. Elsewhere the snake character doesn’t quite work.

But these are wrinkles sure to be ironed out as the show develops on tour; there’s no doubting that its heart is absolutely in the right place and, with Deborah Oyelade sleekly big cat-like as Bagheera, the principals certainly deliver in a retelling which effortlessly suggests the huge continuing relevance of Rudyard Kipling’s tale without ever double-underlining it in over-obvious style.

Barring the hesitations mentioned above, Stilgoe’s songs have plenty of spark when they need it. Mowgli’s identity crisis in song is a cracker in a show which is impressive indeed.